The topic for this wiki entry is Seismic reflection profile. According to Edward J. Tarbuck and Frederick K. Lutgens (2012), “Marine geologists wants to view the rock structure beneath the sediments that blanket much of the seafloor. Marine geologists accomplish this by making a seismic reflection profile. To construct a seismic reflection profile, strong low-frequency sounds are produced by explosions (depth charges) or air guns. These waves penetrate beneath the seafloor and reflect off the contacts between rock layers and fault zones” (p.385-386).
Summary:
In Active Faults In the Sea of Marmara, Western Turkey, Imaged by Seismic Reflection Profiles:
“Turkey is moving westward relative to Eurasia. The Sea of Marmara lies over the direct westward continuation of the North Anatolian Fault zone. In order to determine the more precise the locations of faults, and how they interact, they conducted a four week seismic reflection profiling survey in September 1997. They recorded over 2000 km of high-resolution 2D reflection data, using a 10-gun, 23 L, tuned generator-injector compressed air source. The hydrophone had 96 channels, extending to a maximum offset of 1500m from the ship. The data were bandpass filtered at 8-218Hz at the acquisition stage. Shots were fired at a spacing of 50m. The data was recorded in a two-way time (TWT) of 8 s, at a sample interval of 2ms. Good images of the top 2-3km of the subsurface were acquired, with occasional deeper reflectors also observed. The data were of excellent quality in the deep water regions, permitting clear images of faults cutting recent seafloor sediments, as well as some less active faults, now buried beneath several kilometers of sediment. In the shallower, southern shelf regions, quality deteriorated due to interference from strong water multiples. These strong water multiples suggest a large impedance between the water and the seafloor, indicating that the southern shelf may be made of older, more consolidated sediment. This experiment concentrated on mapping the faults of the deeper regions and how they connect across the Sea. ” (p.223-225).
A total of 40 reflection profiles was recorded across the Sea of Marmara (fig. 1).
Figure 1. Topographic map of the Sea of Marmara with locations of observed faults and the main offshore faults from interpreted seismic reflection profiles. Large faults cutting recent sediments are shown in solid black lines. Tracklines from survey reported here are shown as thin solid lines(Parke 2013).
Figure 2: A representative seismic reflection Profile; Line MAR97-033. Vertical exaggeration at the seabed is 2:1. Inset in each section is an interpretation, showing major faults and sedimentary horizons. “M” is the seabed multiple. (Parke,2012) This profile shoes major faults and sedimentary horizons.
According to Press and Siever:
“Seismic reflection profiling uses artificial sources to generate seismic waves that bounce off boundaries between different types of rock. The reflections recorded are plotted as lines on a seismic section that shows features like faults, folds and lithologic boundaries. The times of the reflections give the depth of the reflecting structures. Seismic reflection is the principal method by which the oil industry explores for oil- and natural gas- trapping structures in sedimentary basins and is also used for detailed studies of the deep crust”.
This is an image of Seismic Reflection Profile:
(Press and Siever 2013)
Here
Is a video for seismic reflection profile. This is a YouTube video called 3D Seismic uploaded by ge0physicsrock. It shows the process of Seismic Reflection Profiles:
(ge0physicsrock-2011)
Work Cited
Parke, et al. "Active faults in the Sea of Marmara, western Turkey, imaged by seismic reflection profiles." Terra Nova 11, no. 5 (October 1999): 223. Academic Search Premier, EBSCOhost (accessed November 1, 2013).
3D Seismic. (2011, August 29). YouTube. Retrieved November 2, 2013, from http://www.youtube.com/watch?v=hxJa7EvYoFI
Tarbuck, E. J., & Lutgens, F. K. (2012). Chapter 13: The Ocean Floor. . Earth science (13th ed., pp. 385-386). Upper Saddle River, N.J.: Prentice Hall/Pearson.
Topic:
The topic for this wiki entry is Seismic reflection profile. According to Edward J. Tarbuck and Frederick K. Lutgens (2012), “Marine geologists wants to view the rock structure beneath the sediments that blanket much of the seafloor. Marine geologists accomplish this by making a seismic reflection profile. To construct a seismic reflection profile, strong low-frequency sounds are produced by explosions (depth charges) or air guns. These waves penetrate beneath the seafloor and reflect off the contacts between rock layers and fault zones” (p.385-386).Summary:
In Active Faults In the Sea of Marmara, Western Turkey, Imaged by Seismic Reflection Profiles:“Turkey is moving westward relative to Eurasia. The Sea of Marmara lies over the direct westward continuation of the North Anatolian Fault zone. In order to determine the more precise the locations of faults, and how they interact, they conducted a four week seismic reflection profiling survey in September 1997. They recorded over 2000 km of high-resolution 2D reflection data, using a 10-gun, 23 L, tuned generator-injector compressed air source. The hydrophone had 96 channels, extending to a maximum offset of 1500m from the ship. The data were bandpass filtered at 8-218Hz at the acquisition stage. Shots were fired at a spacing of 50m. The data was recorded in a two-way time (TWT) of 8 s, at a sample interval of 2ms. Good images of the top 2-3km of the subsurface were acquired, with occasional deeper reflectors also observed. The data were of excellent quality in the deep water regions, permitting clear images of faults cutting recent seafloor sediments, as well as some less active faults, now buried beneath several kilometers of sediment. In the shallower, southern shelf regions, quality deteriorated due to interference from strong water multiples. These strong water multiples suggest a large impedance between the water and the seafloor, indicating that the southern shelf may be made of older, more consolidated sediment. This experiment concentrated on mapping the faults of the deeper regions and how they connect across the Sea. ” (p.223-225).
A total of 40 reflection profiles was recorded across the Sea of Marmara (fig. 1).
Figure 1. Topographic map of the Sea of Marmara with locations of observed faults and the main offshore faults from interpreted seismic reflection profiles. Large faults cutting recent sediments are shown in solid black lines. Tracklines from survey reported here are shown as thin solid lines(Parke 2013).
Figure 2: A representative seismic reflection Profile; Line MAR97-033. Vertical exaggeration at the seabed is 2:1. Inset in each section is an interpretation, showing major faults and sedimentary horizons. “M” is the seabed multiple. (Parke,2012) This profile shoes major faults and sedimentary horizons.
According to Press and Siever:
“Seismic reflection profiling uses artificial sources to generate seismic waves that bounce off boundaries between different types of rock. The reflections recorded are plotted as lines on a seismic section that shows features like faults, folds and lithologic boundaries. The times of the reflections give the depth of the reflecting structures. Seismic reflection is the principal method by which the oil industry explores for oil- and natural gas- trapping structures in sedimentary basins and is also used for detailed studies of the deep crust”.
This is an image of Seismic Reflection Profile:
(Press and Siever 2013)
Here
Is a video for seismic reflection profile. This is a YouTube video called 3D Seismic uploaded by ge0physicsrock. It shows the process of Seismic Reflection Profiles:
(ge0physicsrock-2011)
Work Cited
Parke, et al. "Active faults in the Sea of Marmara, western Turkey, imaged by seismic reflection profiles." Terra Nova 11, no. 5 (October 1999): 223. Academic Search Premier, EBSCOhost (accessed November 1, 2013).
3D Seismic. (2011, August 29). YouTube. Retrieved November 2, 2013, from http://www.youtube.com/watch?v=hxJa7EvYoFI
Press., & Siever. (n.d.). SEISMIC REFLECTION. SEISMIC REFLECTION. Retrieved November 2, 2013, from http://www.earth.northwestern.edu/people/seth/107/Seismology/seismicreflection.htm
Tarbuck, E. J., & Lutgens, F. K. (2012). Chapter 13: The Ocean Floor. . Earth science (13th ed., pp. 385-386). Upper Saddle River, N.J.: Prentice Hall/Pearson.